Fatal error generating packing slip with PHP 7.4

Hi,

Our website is currently running php7.3 and I would like to start using 7.4. Generating packing slips and invoices works fine with 7.3 however, once I upgrade to 7.4 I get fatal errors when I try to generate a packing slip.

This is the error I am getting https://imgur.com/FvwKwpa

Fatal error: Class 'DOMImplementation' not found
/var/www/Moorhouses_new/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/vendor/masterminds/html5/src/HTML5/Parser/DOMTreeBuilder.php (172)
#0 /var/www/Moorhouses_new/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/vendor/masterminds/html5/src/HTML5.php(157): Masterminds\HTML5\Parser\DOMTreeBuilder->__construct()
#1 /var/www/Moorhouses_new/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/vendor/masterminds/html5/src/HTML5.php(89): Masterminds\HTML5->parse()
#2 /var/www/Moorhouses_new/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/vendor/dompdf/dompdf/src/Dompdf.php(478): Masterminds\HTML5->loadHTML()
#3 /var/www/Moorhouses_new/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/includes/class-wcpdf-pdf-maker.php(51): Dompdf\Dompdf->loadHtml()
#4 /var/www/Moorhouses_new/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/includes/documents/abstract-wcpdf-order-document.php(840): WPO\WC\PDF_Invoices\PDF_Maker->output()
#5 /var/www/Moorhouses_new/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/includes/documents/abstract-wcpdf-order-document.php(905): WPO\WC\PDF_Invoices\Documents\Order_Document->get_pdf()
#6 /var/www/Moorhouses_new/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/includes/class-wcpdf-main.php(419): WPO\WC\PDF_Invoices\Documents\Order_Document->output_pdf()
#7 /var/www/Moorhouses_new/wp-includes/class-wp-hook.php(308): WPO\WC\PDF_Invoices\Main->generate_pdf_ajax()
#8 /var/www/Moorhouses_new/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters()
#9 /var/www/Moorhouses_new/wp-includes/plugin.php(517): WP_Hook->do_action()
#10 /var/www/Moorhouses_new/wp-admin/admin-ajax.php(188): do_action()
#11 {main}

Is there anything I can do to resolve this and start using php7.4?

Thanks